Specifications diaphragm cells

The brine feed to the electroly2ers of all the processes is usually acidified with hydrochloric acid to reduce oxygen and chlorate formation in the anolyte. Table 14 gives the specifications of the feed brines requited for the membrane and diaphragm cell process to reali2e optimal performance. 

Membrane Cells. Membrane cells are not subject to the electrode poisoning suffered by mercury cells. They are in this respect similar to diaphragm cells, but the membranes themselves are exceptionally sensitive to brine impurities [77], and brine specifications for membrane cells are more onerous. Section 4.8 discussed the structure and performance of membranes and explained the reasons for this sensitivity. Certain impurities can affect cell performance and the service life of the membranes even when present at ppb levels. Their concentrations in the brine must be rigidly controlled. When this is done successfully and ultra-pure brine is consistently available, service life can be quite long, and test cells have operated well for up to 9 years [78]. 

Each type of cell has its own requirements. Diaphragm cells are perhaps the most forgiving of impurities. While mercury cells can tolerate a higher total concentration because of their lesser sensitivity to the major impurities, they are susceptible to damage by small quantities of certain heavy metals. Membrane cells have the most exacting brine specification and are distinguished front the others by their very low hardness specification. 

There are three basic processes for the electrolytic production of chlorine, the nature of the cathode reaction depending on the specific process. These three processes are (1) the diaphragm cell process (Griesheim cell, 1885), (2) the mercury cell process (Cast-ner-Kellner cell, 1892), and (3) the membrane cell process (1970). 

Table 11. HU series diaphragm cells specific load, cell voltage, and power consumption... 

Ihble 13. Typical brine feed specifications for diaphragm cells... 

Most commonly, diaphragm cells are supplied with well brine on a once-through basis. The treated well brine flows to the treated brine storage tanks, which usually have 12-h capacity. From there the brine is fed to the cell room. The flow to each individual electrolyzer is controlled by a rotameter. If the flow of brine to the cells is suddenly disrupted by failure of the brine feed pump, the rectifiers automatically shut down since an inadequate supply of brine to the cells is potentially unsafe. The specifications for brine for diaphragm cells are given in Table 13. 

Muscle-specific actin HHF-35 42-kD protein in preparations of purified skeletal muscle actin and extracts of aorta, uterus, diaphragm, and heart SDS extracted protein fraction of human myocardium Cell Marque NA HIER... 

Electrochemical gas sensors detect gases based on the electromotive force(EMF) or the current of an electrochemical cell due to the electrochemical reaction of a particular gas. Solid electrolyte which a specific ion can selectively permeate is used as a diaphragm. Potentiometric type gas sensors have been most widely adopted. Among them potentiometric oxygen sensors composed of partial stabilized zirconia have already had practical application and heen extensively used for the feedback control of the air-fuel ratio of automobile engines. The oxygen sensor elements are composed of the following electrochemical cell. 

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